cli: add insert command

The notmuch insert command reads a message from standard input,
writes it to a Maildir folder, and then incorporates the message into
the notmuch database.  Essentially it moves the functionality of
notmuch-deliver into notmuch.

Though it could be used as an alternative to notmuch new, the reason
I want this is to allow my notmuch frontend to add postponed or sent
messages to the mail store and notmuch database, without resorting to
another tool (e.g. notmuch-deliver) nor directly modifying the maildir.

1 files changed, 337 insertions, 0 deletions

diff --git a/notmuch-insert.c b/notmuch-insert.c
new file mode 100644
index 00000000..1228afac
--- /dev/null
+++ b/notmuch-insert.c
@@ -0,0 +1,337 @@
+/* notmuch - Not much of an email program, (just index and search)
+ *
+ * Copyright © 2013 Peter Wang
+ *
+ * Based in part on notmuch-deliver
+ * Copyright © 2010 Ali Polatel
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see http://www.gnu.org/licenses/ .
+ *
+ * Author: Peter Wang <novalazy@gmail.com>
+ */
+
+#include "notmuch-client.h"
+#include "tag-util.h"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+static volatile sig_atomic_t interrupted;
+
+static void
+handle_sigint (unused (int sig))
+{
+    static char msg[] = "Stopping...         \n";
+
+    /* This write is "opportunistic", so it's okay to ignore the
+     * result.  It is not required for correctness, and if it does
+     * fail or produce a short write, we want to get out of the signal
+     * handler as quickly as possible, not retry it. */
+    IGNORE_RESULT (write (2, msg, sizeof (msg) - 1));
+    interrupted = 1;
+}
+
+/* Like gethostname but guarantees that a null-terminated hostname is
+ * returned, even if it has to make one up. Invalid characters are
+ * substituted such that the hostname can be used within a filename.
+ */
+static void
+safe_gethostname (char *hostname, size_t len)
+{
+    char *p;
+
+    if (gethostname (hostname, len) == -1) {
+	strncpy (hostname, "unknown", len);
+    }
+    hostname[len - 1] = '\0';
+
+    for (p = hostname; *p != '\0'; p++) {
+	if (*p == '/' || *p == ':')
+	    *p = '_';
+    }
+}
+
+/* Call fsync() on a directory path. */
+static notmuch_bool_t
+sync_dir (const char *dir)
+{
+    notmuch_bool_t ret;
+    int fd;
+
+    fd = open (dir, O_RDONLY);
+    if (fd == -1) {
+	fprintf (stderr, "Error: open() dir failed: %s\n", strerror (errno));
+	return FALSE;
+    }
+    ret = (fsync (fd) == 0);
+    if (! ret) {
+	fprintf (stderr, "Error: fsync() dir failed: %s\n", strerror (errno));
+    }
+    close (fd);
+    return ret;
+}
+
+/* Open a unique file in the 'tmp' sub-directory of dir.
+ * Returns the file descriptor on success, or -1 on failure.
+ * On success, file paths for the message in the 'tmp' and 'new'
+ * directories are returned via tmppath and newpath,
+ * and the path of the 'new' directory itself in newdir. */
+static int
+maildir_open_tmp_file (void *ctx, const char *dir,
+		       char **tmppath, char **newpath, char **newdir)
+{
+    pid_t pid;
+    char hostname[256];
+    struct timeval tv;
+    char *filename;
+    int fd = -1;
+
+    /* We follow the Dovecot file name generation algorithm. */
+    pid = getpid ();
+    safe_gethostname (hostname, sizeof (hostname));
+    do {
+	gettimeofday (&tv, NULL);
+	filename = talloc_asprintf (ctx, "%ld.M%ldP%d.%s",
+				    tv.tv_sec, tv.tv_usec, pid, hostname);
+	if (! filename) {
+	    fprintf (stderr, "Out of memory\n");
+	    return -1;
+	}
+
+	*tmppath = talloc_asprintf (ctx, "%s/tmp/%s", dir, filename);
+	if (! *tmppath) {
+	    fprintf (stderr, "Out of memory\n");
+	    return -1;
+	}
+
+	fd = open (*tmppath, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL, 0600);
+    } while (fd == -1 && errno == EEXIST);
+
+    if (fd == -1) {
+	fprintf (stderr, "Error: opening %s: %s\n", *tmppath, strerror (errno));
+	return -1;
+    }
+
+    *newdir = talloc_asprintf (ctx, "%s/new", dir);
+    *newpath = talloc_asprintf (ctx, "%s/new/%s", dir, filename);
+    if (! *newdir || ! *newpath) {
+	fprintf (stderr, "Out of memory\n");
+	close (fd);
+	unlink (*tmppath);
+	return -1;
+    }
+
+    talloc_free (filename);
+
+    return fd;
+}
+
+/* Copy the contents of standard input (fdin) into fdout.
+ * Returns TRUE if a non-empty file was written successfully.
+ * Otherwise, return FALSE. */
+static notmuch_bool_t
+copy_stdin (int fdin, int fdout)
+{
+    notmuch_bool_t empty = TRUE;
+
+    while (! interrupted) {
+	ssize_t remain;
+	char buf[4096];
+	char *p;
+
+	remain = read (fdin, buf, sizeof (buf));
+	if (remain == 0)
+	    break;
+	if (remain < 0) {
+	    if (errno == EINTR)
+		continue;
+	    fprintf (stderr, "Error: reading from standard input: %s\n",
+		     strerror (errno));
+	    return FALSE;
+	}
+
+	p = buf;
+	do {
+	    ssize_t written = write (fdout, p, remain);
+	    if (written < 0 && errno == EINTR)
+		continue;
+	    if (written <= 0) {
+		fprintf (stderr, "Error: writing to temporary file: %s",
+			 strerror (errno));
+		return FALSE;
+	    }
+	    p += written;
+	    remain -= written;
+	    empty = FALSE;
+	} while (remain > 0);
+    }
+
+    return (!interrupted && !empty);
+}
+
+/* Add the specified message file to the notmuch database, applying tags.
+ * The file is renamed to encode notmuch tags as maildir flags. */
+static void
+add_file_to_database (notmuch_database_t *notmuch, const char *path,
+		      tag_op_list_t *tag_ops)
+{
+    notmuch_message_t *message;
+    notmuch_status_t status;
+
+    status = notmuch_database_add_message (notmuch, path, &message);
+    switch (status) {
+    case NOTMUCH_STATUS_SUCCESS:
+    case NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID:
+	break;
+    default:
+    case NOTMUCH_STATUS_FILE_NOT_EMAIL:
+    case NOTMUCH_STATUS_READ_ONLY_DATABASE:
+    case NOTMUCH_STATUS_XAPIAN_EXCEPTION:
+    case NOTMUCH_STATUS_OUT_OF_MEMORY:
+    case NOTMUCH_STATUS_FILE_ERROR:
+    case NOTMUCH_STATUS_NULL_POINTER:
+    case NOTMUCH_STATUS_TAG_TOO_LONG:
+    case NOTMUCH_STATUS_UNBALANCED_FREEZE_THAW:
+    case NOTMUCH_STATUS_UNBALANCED_ATOMIC:
+    case NOTMUCH_STATUS_LAST_STATUS:
+	fprintf (stderr, "Error: failed to add `%s' to notmuch database: %s\n",
+		 path, notmuch_status_to_string (status));
+	return;
+    }
+
+    if (status == NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID) {
+	/* Don't change tags of an existing message. */
+	status = notmuch_message_tags_to_maildir_flags (message);
+	if (status != NOTMUCH_STATUS_SUCCESS)
+	    fprintf (stderr, "Error: failed to sync tags to maildir flags\n");
+    } else {
+	tag_op_list_apply (message, tag_ops, TAG_FLAG_MAILDIR_SYNC);
+    }
+
+    notmuch_message_destroy (message);
+}
+
+static notmuch_bool_t
+insert_message (void *ctx, notmuch_database_t *notmuch, int fdin,
+		const char *dir, tag_op_list_t *tag_ops)
+{
+    char *tmppath;
+    char *newpath;
+    char *newdir;
+    int fdout;
+    char *cleanup_path;
+
+    fdout = maildir_open_tmp_file (ctx, dir, &tmppath, &newpath, &newdir);
+    if (fdout < 0)
+	return FALSE;
+
+    cleanup_path = tmppath;
+
+    if (! copy_stdin (fdin, fdout))
+	goto FAIL;
+
+    if (fsync (fdout) != 0) {
+	fprintf (stderr, "Error: fsync failed: %s\n", strerror (errno));
+	goto FAIL;
+    }
+
+    close (fdout);
+    fdout = -1;
+
+    /* Atomically move the new message file from the Maildir 'tmp' directory
+     * to the 'new' directory.  We follow the Dovecot recommendation to
+     * simply use rename() instead of link() and unlink().
+     * See also: http://wiki.dovecot.org/MailboxFormat/Maildir#Mail_delivery
+     */
+    if (rename (tmppath, newpath) != 0) {
+	fprintf (stderr, "Error: rename() failed: %s\n", strerror (errno));
+	goto FAIL;
+    }
+
+    cleanup_path = newpath;
+
+    if (! sync_dir (newdir))
+	goto FAIL;
+
+    /* Even if adding the message to the notmuch database fails,
+     * the message is on disk and we consider the delivery completed. */
+    add_file_to_database (notmuch, newpath, tag_ops);
+
+    return TRUE;
+
+  FAIL:
+    if (fdout >= 0)
+	close (fdout);
+    unlink (cleanup_path);
+    return FALSE;
+}
+
+int
+notmuch_insert_command (notmuch_config_t *config, int argc, char *argv[])
+{
+    notmuch_database_t *notmuch;
+    struct sigaction action;
+    const char *db_path;
+    const char **new_tags;
+    size_t new_tags_length;
+    tag_op_list_t *tag_ops;
+    char *query_string = NULL;
+    const char *maildir;
+    int opt_index = 1;
+    unsigned int i;
+    notmuch_bool_t ret;
+
+    db_path = notmuch_config_get_database_path (config);
+    new_tags = notmuch_config_get_new_tags (config, &new_tags_length);
+
+    tag_ops = tag_op_list_create (config);
+    if (tag_ops == NULL) {
+	fprintf (stderr, "Out of memory.\n");
+	return 1;
+    }
+    for (i = 0; i < new_tags_length; i++) {
+	if (tag_op_list_append (tag_ops, new_tags[i], FALSE))
+	    return 1;
+    }
+
+    if (parse_tag_command_line (config, argc - opt_index, argv + opt_index,
+				&query_string, tag_ops))
+	return 1;
+
+    if (*query_string != '\0') {
+	fprintf (stderr, "Error: unexpected query string: %s\n", query_string);
+	return 1;
+    }
+
+    maildir = db_path;
+
+    /* Setup our handler for SIGINT. We do not set SA_RESTART so that copying
+     * from standard input may be interrupted. */
+    memset (&action, 0, sizeof (struct sigaction));
+    action.sa_handler = handle_sigint;
+    sigemptyset (&action.sa_mask);
+    action.sa_flags = 0;
+    sigaction (SIGINT, &action, NULL);
+
+    if (notmuch_database_open (notmuch_config_get_database_path (config),
+			       NOTMUCH_DATABASE_MODE_READ_WRITE, &notmuch))
+	return 1;
+
+    ret = insert_message (config, notmuch, STDIN_FILENO, maildir, tag_ops);
+
+    notmuch_database_destroy (notmuch);
+
+    return (ret) ? 0 : 1;
+}